跪求大神帮我看看，代码显示没错，就是不能运行

Question

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical"     tools:context=".MainActivity" >     <LinearLayout                 android:layout_width="match_parent"         android:layout_height="wrap_content"         android:orientation="horizontal"          >         <EditText             android:id="@+id/editext1"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_weight="2"             android:text="EditText" />         <Button             android:id="@+id/button1"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:layout_weight="1"             android:text="Button" />     </LinearLayout>     <TextView                  android:id="@+id/textview1"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="TextView" /> </LinearLayout>package com.example.sy1;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.widget.Button;import android.widget.EditText;public class MainActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        final EditText edittext=(EditText)findViewById(R.id.editext1);        Button button=(Button)findViewById(R.id.button1);        final EditText textview=(EditText)findViewById(R.id.textview1);        button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View arg0) {// TODO Auto-generated method stubtextview.setText(""+edittext.getText().toString());}});            }           @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.main, menu);        return true;    }    }